Circuit arrangement and method for identifying a frequency band or channel
The disclosure relates to a circuit arrangement for transmitting uplink and downlink signals between at least one terminal device and at least one antenna, wherein the circuit arrangement comprises a signal coupler for providing a decoupled uplink or downlink signal, a device for providing a reference signal of adjustable frequency, a mixer for mixing the decoupled signal and the reference signal and a filter device for low-pass or bandpass filtering of the mixed signal, wherein the circuit arrangement comprises an evaluation device for evaluating the filtered signal, wherein, depending on the adjusted frequency of the reference signal and on at least one signal property of the filtered signal, a frequency band or channel in which the transmitted signal is being transmitted can be identified, and also to a method for identifying a frequency band or channel.
1. A circuit arrangement for transmitting a signal, wherein the circuit arrangement comprises:
a signal coupler configured to provide a decoupled uplink or downlink signal;
a reference-signal device configured to provide a reference signal of adjustable frequency;
a mixer configured to mix the decoupled uplink or downlink signal and the reference signal to generate a mixed signal; and
at least one filter device configured to low-pass or bandpass filter the mixed signal so as to generate a filtered signal;
an evaluation device configured to evaluate the filtered signal to identify a frequency band or a channel for transmitting the signal based on the reference signal and at least one signal property of the filtered signal; and
a terminal-device-side interface to transmit the signal based on the identified frequency band or channel for transmission.
2. The circuit arrangement of claim 1 , wherein the circuit arrangement further comprises a signal-power device configured to determine a signal power of the filtered signal.
3. The circuit arrangement of claim 1 , wherein a cut-off frequency of the filter device can be adjusted.
4. The circuit arrangement of claim 2 , wherein the reference-signal device is designed as a phase-locked loop or comprises the phase-locked loop.
5. The circuit arrangement of claim 3 , wherein the circuit arrangement further comprises a control device configured to adjust the frequency of the reference signal and a cut-off frequency of the filter device.
6. The circuit arrangement of claim 2 , wherein the circuit arrangement further comprises a signal-detection device configured to detect signal transmission.
7. The circuit arrangement of claim 2 , wherein the circuit arrangement further comprises a switching element, wherein a first port of the signal coupler is connected to the mixer in a first switching state of the switching element, and a second port of the signal coupler is connected to the mixer in a second switching state of the switching.
8. The circuit arrangement of claim 2 , wherein the circuit arrangement further comprises a bypass device configured to transmit the decoupled uplink or downlink signal between the signal coupler and the mixer.
9. The circuit arrangement of claim 1 , wherein the evaluation device is further configured to determine a channel bandwidth of the identified frequency band or channel.
10. A method for transmitting a signal, comprising:
providing a decoupled uplink or downlink signal;
providing at least one reference signal of at least one prespecified frequency;
mixing the decoupled uplink or downlink signal and the at least one reference signal to generate at least one mixed signal;
filtering the at least one mixed signal to generate at least one filtered signal;
determining at least one signal property of the at least one filtered signal; and
identifying a frequency band or a channel for transmitting the signal based on the at least one reference signal and on the at least one signal property of the at least one filtered signal; and
transmitting the signal based on the identified frequency band or channel for transmission.
11. The method of claim 10 , wherein the at least one reference signal comprises a plurality of reference signals of different frequencies, wherein each of the plurality of reference signals is mixed with the decoupled uplink or downlink signal to generate a plurality of mixed signals that are filtered to generate a plurality of filtered signals.
12. The method of claim 10 , further comprising:
determining a cut off frequency of a filter that generates the at least one filtered signal.
13. The method of claim 10 , wherein identifying the frequency band or the channel comprises identifying the frequency band, the method further comprising:
identifying a channel of the frequency band.
14. The method of claim 13 , further comprising:
identifying a channel bandwidth of the channel.
15. The method of claim 10 , further comprising:
after identifying the frequency band or the channel, starting monitoring the at least one signal property; and
identifying an additional frequency band or an additional channel for transmitting.
16. The method of claim 15 , wherein monitoring the at least one signal property and identifying the additional frequency band or the additional channel are carried out simultaneously.